Weird...I genuinely hope this can get sorted. MC handles my largish library better than anything else I've used
One thing that I find helps immensely is to make view schemes that don't look at ALL the files at once. I do have some all files views but I normally use much smaller chunks, makes a HUGE difference. I've made tagging views as well that only look at audio files for example, and ignore the .log, .cue, .jpg etc which eliminates a lot of ancillary files bogging things down
I've never had stuttering with converting files, but if I'm ripping while listening I sometimes do. These are processor intense operations though, if I have a lot to convert I let it run overnight
I never have issue getting art, etc. but I always do those in smaller chunks as well (I never select 30+ albums worth at a time...)
I've never had the views revert to default after a crash! Sometimes after a crash my most recent changes don't get saved but it's never too far back before the crash
The biggest improvement I ever had with MC was when I put the database (library) on an SSD, and bought a bunch of 4Tb high rev internal HDD's that I use for main library, and switched the big USB drives to backup